Energizer assembly



P. B. FERRARA ENERGIZER ASSEMBLY Filed Aug. 13, 1954 March 25, 195,8

A INVENTOR Peter vB. VFrrcrra ATTORNEY United States .Patent ENERGIZER ASSEMBLY Peter B. Ferrara, Silver Spring, Md., assignor to the United States of America asire'presented :by the SecretaryTofthe'Army Application August 13, 1954, Serial No. 449,811

Claims. (Cl. 102770,-2)

(Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured by or for the Goverment for governmental purposes without the payment to me of any royalty thereon.

This invention relates to energy sources. More particularly it is a method and device for actuating an electromechanical transducer in order to produce, across the transducer, an electric potential difference. The essence of the invention is that an explosive primer is used to stress the transducer (a minimum of energy being required to activate the primer).

In electromechanical transducers of the piezoelectric type a potential diiference appears across the transducer when the transducer is deformed in such a manner as to set up stresses within it. The magnitude of that potential difference is dependent upon the manner and the degree to which the transducer is stressed.

One object of this invention is a dependable electrical energy source where small amounts of energy are required.

Another object of the invention is an energy source requiring a minimum of space for its accommodation.

A further object of the invention is a device for stressing an electromechanical transducer in order to consistently produce a required voltage.

A still further object of the invention is a method of assembling an explosive primer with an electromechanical transducer such that the activation of the primer will stress the transducer the required amount.

An additional object of the invention is a method for activating an explosive primer designed to stress an electromechanical transducer.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from the following description and drawing wherein:

Figurel is a longitudinal sectional View of the invention.

Figure 2 is a fragmentary longitudinal sectional view of a modification of the invention shown in Fig. l.

In the present invention an electromechanical transducer such as a piezoelectric crystal or a prepolarized ceramic is stressed by the explosive force of the primer. In the preferred embodiment of the invention as shown in Fig. l a piezoelectric ceramic cylinder 1 and an explosive primer or charge 2 are contained within outer case 3. Ground contact 4 spaces crystal 1 and primer 2 and assures positive electrical contact between the lower surface 5 of the cylinder and outer case 3. The outer case constitutes one energizer terminal. The other energizer terminal is contact 6 which is in juxtaposition with the upper surface 7 of cylinder 1. Contact 6 is provided with depending portion 8 which extends through but remains out of contact with centrally apertured base 9 of outer case 3. Recess 10 is provided in contact 6 and is adapted to accommodate a jack plug, not shown. Insulator 12 maintains contact 6 out of elec trical contact with outer case 3. Spacer 13 is provided to position primer 2 within outer case 3.

. Patented Mais 25, v 11953 Outer case 3 -is 4rolled .over flange 21 of cup-shaped member 14 tov secure said member to the remainder of the 'energizer assembly. Located within cup-shaped member 14 is striker V15 which is biased away from primer 2 by helical s'pring 17 -actin'g against shoulder '16 of striker .15. A -safety `means comprising a pin 158 extends through aperture 19 of cup-shaped member 14 to .engage `notch 20 of striker .15 for `the purposeof'maintaining said striker releasably affixed to member .14 to prevent the said *striker "from prematurely engaging primer .2. The extraction fof pin 18 maybe accomplished on .setback by any of thejw'ell 'known means `Such :as by a linkage, not shown, cooperating with a setback sensitive device not shown.

Assuming, therefore, that pin 18 has been removed, and a projectile, not shown, containing the invention is subjected to a rapid deceleration as when the projectile comes to earth after being iired from a gun, striker 15 moves forward against the force of spring 17 to engage primer 2. The shock from the resulting impact is transmitted to cylinder 1 which is deformed and stressed whereby a potential diiference appears across cylinder 1 due to its property of providing a voltage when stressed. The same voltage appears also across outer case 3 and contact 6 vecause they are in current conducting relationship with cylinder 1.

A modication of the invention is shown in Fig. 2. The striker 15a is provided with a stern 22 which extends through aperture 23 in the base of cup-shaped member 14a.

In the modification shown the striker 15a is directly activated whereas in the embodiment shown in Fig. l the striker moves when acted upon by an inertia force. The energizer shown in Fig. 2 is used to function a booby trap or land mine. For example when a booby trap is positioned under the cus'hion of a chair, and the chair is sat upon, stem 22 is forced inwardly causing striker 15a to move against the bias of spring 17 to detonate primer 2. The result is that the cylinder, as shown in Fig. 1, is stressed and produces the voltage to function the booby trap.

It will be apparent that the embodiments shown are only exemplary and that various modications can be made in construction and arrangement within the scope of the invention as dened in the appended claims.

I claim:

1. An electrical energizing device comprising an outer case, an electromechanical transducer and an explosive primer contained within said outer case, the primer being adapted to stress the transducer, contact means engaging opposing surfaces of said transducer and consti tuting the two terminals of the energizer, and actuating means for firing said explosive primer to stress said trans ducer and generate a voltage therein.

2. An electrical energizing device comprising an outer case, an electromechanical transducer, and an explosive primer contained within said outer case, a ground contact spacing said transducer and said primer, the said ground contact and said outer case being in current conducting relationship, a second contact engaging the opposite end of said transducer and acting as one terminal of the energizer, the said outer case constituting the other energizer terminal, and actuating means for iii-ing said explosive primer to stress said transducer and generate a voltage therein.

3. An electrical energizing device comprising an electromechanical transducer, an explosive primer adapted to produce a pressure wave when activated to stress said transducer, a contact positioned adjacent one side of said transducer and spacing said transducer and said primer, a second contact positioned adjacent the opposite side of said transducer and constituting one terminal of said energizer, an outer case containing said transducer and primer and engaging said first Contact to constitute the other terminal of the energizer, and actuating means for tiring said explosive primer to stress saidtransducer and generate a voltage therein.

4. The invention in accordance with claim 3 wherein said explosive primer activating means comprises a housing, the said housing being affixed at its upper end to the said outer case at its lower end, a striker contained Within said housing, means adapted to bias said striker toward the lower end of said housing, said striker adapted to engage and activate said primer when the energizer is subjected to a predetermined force.

5. The invention iu accordance with claim 3 wherein said explosive primer activating means comprises a housing, the said housing being atixed at its upper end to said outer case at its lower end, a striker contained Within said housing, means adapted to bias said striker toward the lower end of said housing, a stem axed to the lower end of said striker and extending through an aperture in said housing at the lower end thereof, the said stem adapted to cause said striker to activate said primer.

References Cited in the ile of this patent UNITED STATES PATENTS 2,544,077 Gardner Mar. 6, 1951 FOREIGN PATENTS 277,052 Switzerland Nov. 1, 1951 

